Australian time zones

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(Redirected from Australian Eastern Standard Time)

In Australia, the keeping of standard time is divided into three time zones: Australian Eastern Standard Time, Australian Central Standard Time and Australian Western Standard Time. These correspond to UTC+10, UTC+9:30 and UTC+8 respectively.

1 Time zones
2 Daylight saving
3 Accuracy and standards
4 References

Time zones

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The standardisation of time in Australia began in 1892, when surveyeors from the Australian colonies gathered in Melboune for the Intercolonial Conference of Surveyors. The delegates accepted the recommendation of the 1884 International Meridian Conference to adopt Greenwich Mean Time (GMT) as the basis for standard time, and in line with common practise in other parts of the world, devised a system of of time zones with offets in multiples of one hour from GMT. In the years that followed, the colonies enacted legislation to this effect, with Western Australia leading GMT by 8 hours, South Australia by 9 hours, and Queensland, New South Wales, Victoria and Tasmania leading by 10 hours. The three time zones became known as Western, Central and Eastern Standard Time. In 1898, South Australia moved its standard time to GMT+9:30, a system that remains in place today. Since that time, the only major change has been the adoption of Central Standard Time in Broken Hill, New South Wales, and the use of GMT+10:30 on Lord Howe Island. The Australian Capital Territory and the Northern Territory maintained the standard time zones of their parent states (New South Wales and South Australia) when they separated from them in 1910 and 1911. The non-integer offset of Central Standard Time has at times been subject to criticism, with unsuccessful proposals in 1986 and 1994 to adopt GMT+10 or revert to GMT+9 in South Australia.

Daylight saving

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Only the states and territories in the south east of the country (South Australia, New South Wales, the Australian Capital Territory, Victoria and Tasmania) observe daylight saving time. This has resulted in three time zones becoming five for half the year. South Australia follows Australian Central Daylight Time (ACDT, UTC+10.5) and the south eastern states follow Australian Eastern Daylight Time (AEDT, UTC+11). Of the states that observe daylight savings, most begin on the last weekend in October, and end on the last weekend in March. An exception to this is the island state of Tasmania, which (due to it's southern latitude) begins daylight savings earlier, on the first weekend on October. Public opinion of daylight saving in Queensland is divided. The Queensland-New South Wales border area is heavily populated and as a result businesses are inconvenienced by the difference in time. Generally, the urban south east corner would prefer daylight savings, and the rural towns and farming regions elsewhere would not, although this is a very generalised view.

Accuracy and standards

Although Australia has maintained a version of the atomic time scale Universal Coordinated Time (UTC) since the 1990s, GMT remained the basis for the standard time of all states until 2005. In November 2004, the Attorneys General endorsed a proposal from the Australian National Measurement Institute to adopt UTC as the basis of all Australian standard times, thereby eliminating the effects of slight variations in the Earth's rotation rate that are inherent to mean solar time. New South Wales and Victoria enacted legislation to this effect, commencing on the 1st of September 2005. Other states are expected to follow.